Retractable landing gear



May 20, 1930. G. LoENlNG RTRACTABLE LANDING GEAR Filed oct. 27; 1927 5 Sheets-Sheet l ATTURNEY May 2.0, 1930- G. LOENING 1,759,197

RETRACTABLE LANDING GEAR Filed Oct. 27, 1927 5 Sheets-Sheet 2 May 20, 1930. G. LoENlNG RETRACTABLE LANDING GEAR.

l Filed Oct. 27, 1927 3 Sheets-Sheet 3 A TTHNEY 'Patented May 2o, 1930 UNITED STATES PATENT OFFICE GROVER IOENING, OFVNEW YORK, N. Y., ASSIGNOR TO LOENING- .AERONAUTICAL ENGINEERING CORPORATION, A CORPORATION OF NEW .RETRACTABLE YLANDING GEAR YORK Application GiL'ded-October 27, 1927.` Serial No. 229,019. i

The present invention relates to retractable or folding landing'gears for airplanes, particularly of those ofithe amphibian, seavplane or eflying boat kinds, a'nd is more especially in the'nature of an improvement upon the type of structure disclosed in United States Patent No. 1,563,384, granted' to meDecember 1, 1925, though features of the invention are not conned for their application to a single plan of construction. The general and specific objects ofthe invention and the advantages to be derived froml its use will appear more fully .as the following description of a preferred form roceeds, and the invention will be particu-y arly pointedout in the appended claims. In the drawings: F ig.: 1 is an elevation, partly in section and ith certain elements omitted, of a portion 2o of an .amphibian lull equipped with a land` inggear constructed lin accordance with the invention, the gear being in extended position;

Fig. 2 is a transverse section, parts being brokei away, of the structure shown` in Fig.

Fig. 3 is'a view similar to Fig.'2, on a )larger scale and showing the landing gear in its retracted position. The body of themachine comprises an upper portion 1 and a lower or hull portion 2, referably constructed as a unit, and provided with transverse bulkheads 3 and 4 forming walls yof a comfpartment 5 open at opposite sides ofthe hull and separated Afrom the `buoyant sections thereof. In the sides ofthe hull, intersectling the space 5, are wheel pockets 8 for re! ceiving the landing wheels 10 when the latter are in their retracted positions.

apex or upperouter corner of `or translatable strut 22, and

oneoe'nd to a collar or yoke 15 secured ,to the member 11 adjacent the'hub of the wheel, l and are braced longitudinally of the hul-1 by webs 14a and cross piece 17. At their upper ends, the struts 141: are joined to struts 16 55 which extend inwardly to the ivot upon which the member 11 is mounted), Secondary bracing struts 18 join intermediate p0rtions of the struts 14 with the pivotfor the frame. From Figs. land 2 it will be obvious that the construction ijustv described provides a rigid butV lightv triangular or pyramidal frame of considerable width fore and aft, the wheel being carried 'at the lower outer corner. of *the frame, and the upper outer corner being utilized in Va manner which will be described, Iunusual structural strength to resist the various stresses encoun-' tered being obtained. In order to further' strengthen the structure against such strains, a rod 19.. extends betweenthe pivot' point of the frame and an anchoring bra'cket19a se cured to the hull ina forwardly located p0- sition, and an additional diagonal bracing member comprising longitudinal members' 20, 20a arid cross struts 20", 20, is pivoted at one end to the bracket 19'i and secured at its opposite end to thel yoke 15.

A rocker-arm 21 r'forming an important element of tlie invention, is pivoted at the the triangle formed by the juncture of the struts 14 and y "A16, this member being preferably in the form of abell-crank having a short arm extending outside the triangular frame, to which is pivoted the outer end of the actuating link a long arm extending within the triangular frame. The

end of the crank arm within the frame is The landin gear includes a palr of tri` angular whee -carrying frames pivoted toy formed to receive the strands of an A'elastic shock-absorbing cable 23 looped "about Kthe cross-piece 17. v e r Referring now to Fig.b 2, it will bev seen thatthe rigld ivotal lwheel-carrying frames, when in'exten edposition, are resiliently sus- 95 tained through the medium of the shock- Y absorbing elements 28 and the rocker-arms 21, the latter rocking at one ointv on the frames and fulcrumed at anot er point on the actuating links 22. "The upward thrust on the vheels caused by landing shocksl swings the frames about the pivots 12, this action in turn swinging the long arms of the bell cranks 21 inward and upward. Motion of the bell cranks in this direction is 'resisted by the elasticvcables 23, which serve to absorb the-landing shocks unless the-latter are unusually. severe, in which case the arms of the bell cranks may be moved in until ,their further motion is arrested by contact with stirrups 24 attached to the members 11` 'ggjected Furthermore,they end themselves to quick and very easy operation by simple manual means employing cables.

Sli traveler blocks 28 are mounted on each of t e rods 25 and have pivoted thereto ao'the inner ends of the links 22, theouter ends of which are ivoted to 0the short arms of the rockers 2 1. g the blocks 28 is controlled by cables 29 and 30, the` former passin over pulleys 3l and as 32 to drums 33 and t e latter over pulleys .34 and 35 to the same drums, the cables 29 and30 however being wound on the drums in opposite ldirections. The drums- 33 are mounted on a common shaft 36 secured to o the upper' ortion 1 of the hulland this shaft carries a riven s rocket 37 connected by a chain 38 with a in a. position easily reached bythe pilot and actuated by a crank handle 40. The sprocket 39 is formed with a ratchet wheel 41 adapted to be engaged by either jaw of a reversible double pawl 42, the osition of which is controlledv y` a hand ever 43 and spring 44. This reversible device permits of operation 5c of the cable operating means in one direction only, in'one positionof the device, and in the opposite direction only when the device is in the other position.

From the' figures andthe foregoing descri tion the action of the mechanism 1n ex-` ten g and retracting the wheels and frames will be largely obvious, rotatibn by the pilot tended and fully retracted positions, and to gear in this position the cables are again in he position and movement of.

rive sprocket 39 mounted tended position, they are held against re` traction by links 22 acting as thrust members. The combined weight of the wheels and frames is substantial, andin order to aid in moving them both from the fully exyieldingly resist theirvmovement in both directions past a position of equilibrium, elastic cables 45 are provided, each of which-is in the form of a closed loop passing throu h an eye 46 at the outer end of one oi the lin s 22 and over the pulleys- 47 and 48 secured to the member 27". In the position shown in Fig. 2 the cables 45 are in tension and their tendency is to swing the Wheel frames about so vthe pivots 12, thus counterbalancing a sub- -stantial amount of the-weight of .the wheels and frames and aiding in lifting the wheel frames toward their retracted position. As the frames are moved toward the fully retracted position shown in Fi 3, the cables 45 move to a position such t at one -leg of each triangular loop intersects a wheel pocket and lies in the path of the wheel, thereby forming a resilient check against which the wheel strikes as it moves toward its fully retracted position. The wheels, when fully retracted,l stretch the cables in' a manner clearly shown inthe ligure, so that with the tension, the resulting fo rce aiding in moying the wheels out of their pockets when it' is desired to extend the gear., The elastic cables also act frictionally and tensionally to keep the wheels from spinning'when the plane isv motion with the-landing gear folded. Vhen the landing gear is extended these elastic cables act first to aid in starting the wheels. and frames, which are then folded inwardly of the vertical center lines, and later when the force of gravity acts with the motion they act to counterbalance in a substantial measure this -added force. An important function ofthe cables is to equalize, or approximately equalize, the effort required of the operator` in folding and extending the gear.J In this connection the buoyant ei'ect of the wheels in water is lalso to be taken into consideration in determining the tension to be put into Athe cables.

Many .changes and modifications iii' the precise form of the preferred embodiment hereinbefore described may be made without departing from the scope ofthe invention. While the landing gear has been shown applied to a boat or central flotation body, it will be evident that by appropriate minor modification the two halves of the gearf. may be applied to laterally spaced iloats of-seaplanes. 'Y

IclIlim: 1 d I A a an ing ar a.v wheel carrym' frame mounted toswg between an extende and a retracted position, a link serving to v hold the frame in extended position, a mem- 130 i `member rockingly connected to the frame and also to the link, and shock-absorbing means connected to therocker member.

.3. In a landing gear, a triangular wheel carrying frame mounted to swing between an extended and a retracted position, a link serving to hold the frame in extended posiangle and pivotally connected vat another tion, a rocker member at the afiex of the trivpoint with the link, and .shock-absorbing means connected-to 'the rocker member.

4.-. In' a landing gear, a wheel carrying frame mounted to swing between an extended and a retracted position, a link serving to hold the frame in, an extended position, a Acrank rockable on the frame and having a long arm and a short arm, the latter pivoted to the link, and shock absorbing means between the long arm and the frame.

5. In la landing gear, a wheel carrying frame mounted to vswing between an extended and a retracted position, a link serving to hold the frame in extended position, a member rockingly-connected to the frame and also to the link, shock absorbing means con-v nected to the rocker member, andmeans on the frame for limiting the movement of said rocker member.

6.' In Ia landing ear, a pivoted member mounted at one en spaced pairs `of struts secured to `said member to forma double triangular framework, a crank pivoted between said spaced struts at the apex of the triangle, 'said crank com rising an arm extending from the frame, an an arm extending in another direction, an4 elastic cable secured to said firstmentioned arni and to the `frame and resisting rotation in one direction of the crank about its pivot, and a link pivotally secured to said last-mentionedarm to hold the framer r in a relatively fixedposition.k

7. A retractable landing ear comprising wheel-carryiiig-frames mova le past a point of equilibrium between retracted and extended positions, and resilient meansoperatively associated with the frames to counterbalance (pivot inwardly 'of the triangular 9. In an amphibian machine, the combination with `a retractable landing gear comf prising pivoted wheel-carrying frames and means for swinging the frames between extended andl retracted positions, of elastic cables operatively connected to the frames and to spaced fixed points on the machine to form closed loops, said loops exerting a counterbalancing lifting force onthe wheels andfraines vin both the extended and retracted positions.

10. In an amphibian machine, and in combination with a retractable wheeled landing gear and means for operating the same, means for elastically counterbalancing the wei ht ofthe ear, said counterbalancing means eing so isposed as to press against the wheels in 'theretracted position to keep them from spinning.

11. The combination with a retractable landing gear and cable means for operating the same, a handle for operating said cables,

a ratchet wheel, and a reversible pawl cooperating with said ratchet wheel to permit the handle to be turned in one direction only in 011e of its positions, and in the reverse direction only when it is in the other of its positions, a handle for shifting said pawl, and a resilient operating connection between said pawl and said handle.

GRovna LoENiNc.

it as it approaches both extended and retract ed positions.

8. In' an amphibian plane, a 'iioat having a pocket, a' landing wheel, a pivoted frame earryingsaid wheel and arranged to swing it downwardly to a retracted position-in the pocket, means for swinging the frameto retracted position, and an elastic cable connected with the frame and the -oat and arranged to yieldingly resist the movement of the wheel to retracted positionA in the pocket.

' iso 

